1. Field of the Invention
The invention relates to a method for the operation of a wind power plant, wherein in particular the wind power plant will be or is shut down after a shutdown signal is triggered by a safety shutdown device that is logically superordinate to an operating control system. The invention also relates to an energy supply system with at least one wind power plant. Moreover, the invention relates to a safety chain of a wind power plant and a wind power plant.
2. Description of Related Art
As a general rule, a generic wind power plant has a rotor, at least one angle-adjustable rotor blade, a mechanical brake device for braking the rotor and an operating control device and a safety system.
The mechanical brake device engages, in the case of a wind power plant with gearbox on the quickly rotating side of the drive train. The generator with its rotating part called a runner is also located on this side. The mechanical brake device can also be arranged on the slow side of the drive train, i.e. on the side between the gearbox and rotor blades. But the wind power plant can also be designed without a gearbox so that the brake engages in the area of the rotor hub or the generator runner. Within the framework of the invention, the term rotor refers, in particular, to the terms drive train, fast shaft, generator runner, gearbox, rotor shaft (=slow shaft), rotor hub and rotor blades. A braking of the rotor means, in particular, the braking of the drive train.
Methods for the operation of a wind power plant and wind power plants are generally known. One such example is the textbook entitled “Windkraft Systemauslegung, Netzintegration und Regelung” (Wind Power System Design, Grid Integration and Control), Siegfried Heier, 4th Edition, B. G. Teubner, February 2005.
The operation of wind power plants and wind power plants themselves is critical in terms of their design, in particular with respect to security concerns. In particular in the case of strong winds in connection with a network outage, in which the aerodynamic torque created by the wind in the rotor meets no resistance from the generator, it can lead to extreme tower loads, in particular tower foot bending torques, uncontrolled blade angle adjustments and, if necessary, even the triggering of a safety chain. Due to the failure of the network or more generally due to a load rejection of the generator, the rotor begins to accelerate in strong wind until the brake system of the wind power plant begins to brake the rotor. Depending on the strength of the brake power, loads of varying strengths are exerted on the wind power plant.
Moreover, a wind power plant has a safety concept and a corresponding safety system. The safety concept hereby includes all devices, modes of operation and handling instructions that ensure that a wind power plant remains in a safe state even when malfunctions occur and the operating control system fails.
The safety system of a wind power plant has devices that are logically superordinate to the operating control system. Overall, the safety system cannot be deactivated by an unwanted intrusion or an accidental operation. The system is activated when safety-relevant threshold values are exceeded or the operating control system loses management of the wind power plant, whereby the unit cannot be maintained in the operating range. The safety system also includes devices that prevent an unwanted startup of the wind power plant, e.g. for maintenance work or suchlike.
The safety system usually also includes a safety chain, wherein the safety chain is a central device of the wind power plant. When a safety-relevant threshold value is exceeded, the protection devices are triggered by the safety chain, regardless of the operating control system. Protection devices in this connection are the aerodynamic and/or the mechanical brake system, the devices for network separation of the generator or of the generator/converter system and the emergency shutdown protection devices or safeguards and the main switch.
Moreover, a safety device for a wind power plant is known from DE-U-20 2005 014 629. Furthermore, a method for the monitoring of a wind power plant and a wind power plant are disclosed in DE-C-101 15 267.
The object of the present invention is to ensure the safe operation of a wind power plant, in particular after a safety shutdown triggered by a safety chain.